Electrical relay



vJune 6, 1944. N- F, AGNEW 2,350,663

ELECTRICAL RELAY Filed Aug. 21, 1942 Patented June 6, 1944 2,3/51663 ELECTRICAL RELAY Norman F.- Agnew, Penn. Township, Allegheny County, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application August 21, 1942,'sern1 10.455576 Claims. (Cl. 209-93) My invention relates to electrical relays, and

particularly to electrical relays of the sensitive polarized type suitable for use in railway signaling systems.

In the design of compact sensitive polarized relays the problem of pivoting the armature is one of major diculty. It is known that the greatest relay eill'ciency can be obtained when the armature is pivotally supported in the center so that the flux in the air gaps at both ends of the armature can do useful work. However. when the armature is pivoted in the center, it has heretofore been necessary in order tol obtain full efliciency to split the energizing winding into two coils, one of which is disposed on each side of the pivots. This complicates the design, and increases the cost of manufacture, and to get away from the disadvantage of the two coil structure and at the same time eliminate the pivots, other relays have been designed. with a hinge spring at the bottom, the amature in some cases acting as the spring. 'Ihis latter construction, while better mechanically, is less elcient electrically.

, One object of my present invention yis to provide a compact sensitive polarized relay which combines Ithe advantages of both types of relays referred to above.

Another object. of my invention is to provide an improved armature construction together with an improved means for supporting the armature in relays of the type described, which construction and supporting means will enable an energizing winding wound into a single coilV to be A further object of my invention is to decrease the cost of manufacture and facilitate the maintenance of polarized relays of the type described.

. According to my invention, the relay armature is constructed of tw magnetizable strips secured to the opposite sides of a non-magnetizable spring. The spring is secured in place at one end, and the strips and spring extend with clearance through the relay winding which is in the form of a single coil. The strips are secured to the supporting spring intermediate its ends and cooperate at their opposite ends with pairs oi' confronting pole pieces which are polarized as by a permanent magnet, whereby when the relay is energized, the armature pivots about a point located approximately in the center of the winding. This provides a spring armature mounting with the advantages of center pivot operation, and in addition the non-magnetizable spring acts as a pins are required. The free end of the non magnetizable spring actuates the relay contacts.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe one form of relay embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view partly in elevation and partly in section showing one form of relay embodying my invention. Fig. 2 is a top plan view of the relay shown in Fig. 1.

Similar reference characters refer to.similar..

Parts in both views.

Referring to the drawing, the relay in the form here sh`own comprises two ll-shaped yokes I and 2 of m'agnetizable material secured at their upper ends by means of screws 3 to a top plaie 4 of suitable insulating material, such as a phenol condensation product, and at their lowerl ends by means of screws 5, to a bottom plate i, also of suitable msulating'material. The yokes I and 2 are disposed with their upper legs Ia and 2a, and their lower legs Ib and 2b, in spaced confronting relation, and are constantly magnetized by U-shaped permanent magnets l the ends of which engage the yokes at their sides.

core pin so that on polar stick relays no core between the confronting ends of the yokes I and 2 and supports an armature assembly which, as here shown, comprises twomagnetizablestrips 8 and "secured intermediate their ends to the opposite sides of the leg 8a intermediate its ends.

As illustrated, the strips are riveted to the leg la. but it will be' understood that any suitable means may be employed for fastening the strips "o the leg. The upper andv lower ends of the strips 9 and Ill extend between, and cooperate with, the confronting ends of the upper and lower legs of the vmagnetiz'able yokes I and 2 in such manner that the armature assembly Ais free to move between a normal extreme position in which the upper end of the strip I0 engages the end of the leg 2a of the yoke 2 and the lower end of the strip a engages the end of the leg Ib of the yokeA I, and a reverse extreme position in which the upper end of the strip 9 engages the end of the leg la of the yoke I 'and the lower end of the yoke 2.

A hollow spool I I having a coil I2 wound thereon surrounds the armature assembly with some clearance between the upper and lower legs of the yokes, and vis 'held in the proper vertical position by engagement of the spool headsv with the legs of the yokes, and in the proper horizontal positipnby meansfof notches II'a'in the spool headswhich notches receive the yokes I and 2 at their medial portions. The leads I2a and I2b of the coil"4 I2 are secured to terminal posts I3 and I4 mounted in the top plate 4.

The. upper end of the long leg 8a, of the spring I 8.projects upwardly withsome clearance through an opening 4a in the top plate 4, and is providedf with bifurcations 8b which straddle a movable contact'finger I5 intermediate its ends. The iinger I5 is secured at' one end to aterminalblock I6 mounted on the top plate 4, and cooperates at its free end with a fixed contact linger I'I or I8 to closel a normalcontact. I5-I1 or a. reverse contact I5-I8 according as the armature asy sembly is moved to its normal or its reverse exing strips 2I which are fastened to the opposite sidesof the nger as by rivets 22, and which 'serve to insulate'the finger from the spring.I

, ,Assuming that the right-hand encisaof. the per- "m'anent magnets I'a-re north poles and the oppo- Vsite ends south poles, both legs of yoke 2 will vbecome north poles while both legsvof yoke yI will become south poles. Under these conditions, flux willlpass from` yoke '2 toyoke I. This flux will distribute itself in therair gaps Abetween the con- .y 'a 'fronting ends of vthe legs of. the yokes` in such a y, v.way as to allowvthe greatest amount of -flux to 'fiow., That is to say, when-the armatureassemv ."bly is swung to the normal extreme position in ,w hich it is shown4 in the drawing, the greatest partfof the flux which `passes from the yoke 2 to= the yoke I will flow downwardly through the upper'end of the armature strip I0, thence across- Vthe air gap formed between the strips I0 and 9 by the spring 8, and then downwardly through l the lower end of the armature strip 9; but when thefarmature assembly/is swung to its `reverse extreme position, the greater part of the flux will thestrip I 0,1thence across the air gap formed armature' with respect to the confronting ends of the' legs of the yokes Il ,and 2.` When the armature is midway between its two extreme positions, there is no polarizing flux through the armature in the direction of 'its length because both ends of the armature are at the same magnetic potential, and under these conditions all of the 'flux which passes from the yoke 2 to the yoke I will pass through the confronting legs 2a and Ia, and 2b and Ib.

When the energizing coil I2 of the relay is supplied with current, the upper end of the armature assembly will become a north pole and the lower end will become a south pole, or vice versa, according as the coil is supplied with cur-1 rent of reverse polarity or with current of normal polarity. Assuming that the armature assembly occupies its normal extreme position in which it is shown in thedrawing and that the operating winding is supplied with current of reverse polarity, the upper end of -the armature assembly will be repelled from the leg 2a of the yoke 2 and will be attracted toward the leg Ia of the yoke 2, andthe lower'end will be repelled from the leg Ib of the yoke I and will be at-v tracted toward the leg 2b of the yoke 2.. As a result, the armature will quickly move from its normal position to its reverse position and will thereby open the normal contact I5-I1 of the relay and close the reverse contact I5-I8. As

soon as the armature reaches its reverse position, the current can then be removed from the coil I2 and the armature assembly will remain in its reverse position and will hold the reverse contact closed by virtue of the polarizing flux passing through the armature as will be readily understood.

If, when the armature assembly occupies its reverse position, the operating winding is supplied with current of normal polarity, the upper end ofthe armature assembly will then be repellel` from the leg Ia of the yokey I and will be attracted toward the leg 2a of the yoke 2, while the lower end of the armature assembly will be repelled from the leg 2b of the yoke 2 and will be attracted toward theleg Ib. The armature ymay be removed from the coil I2 andthe armature will then remain in the position shown. If, when the armature occupies its normal position, current of normal polarity is supplied to the coil I2, or if, when the armature occupies its reverse l' position, current of reverse polarity is supplied to then flow upwardly through the lower end of the'coil-l I2, the armature will be held in theposition which it then occupies in a manner which will be readily understood without further detailed description.v

`It should be particularly pointed out that with -the relay constructed in the manner described when the armature assembly moves from either extreme position to the other, the spring 8 flexes in such a way that the 'assembly in effect pivotsv about' a point approximately at the center of the coil -I2. This provides a spring armature mounting withthe advantages of center pivot operation and still permits the coil I2 to be wound on a single spool. Thecost ofthe relay is thereby. decreased and the assembly is greatly facilitated.

It should also be particularly pointed out that with'the construction shown, since the flux passing lengthwise through the armature has to traverse the air gap formed between the two armature strips 9 and I0 by the phosphor bronze spring 8, this spring acts as a core pin, so that on polar stick relays no core pins are required. Additional non-magnetic spacers -may be used between the armature strips 9 and I0 andthe spring 8, if required.

sitive compact polarized relay using a minimum number of simple parts all of which are easy to machine and assemble, whereby the relay can it is understood that various changes and modiilcations may be made therein within the scope .of the appended claims without departing from the spirit and scope of my-invention.

Having thus described my invention, what I claim is:

1. An amature assembly for a relay comprising a ilexible non-magnetic spring secured at one end in a xed position, and two magnetizable strips secured intermediate their ends to the opposits sides of said spring intermediate its ends in such positions that the longitudinal axes of said strips and said spring are substantially parallel, said spring serving as a resilient support for said assembly and also serving to provide a non-magnetic gap between said strips, and contact operating means secured to the free end ofy said spring. i

2. A relay comprising a pair of U-shaped yokes disposed with their legs in spaced confronting relation 'to form air gaps, means connected with said Vyokes for polarizing them, a flexible spring of non-magnetic material having one end fixed and extending through said air gaps, two magnetizvable strips secured to the opposite sides of said spring and having their ends disposed in said air gaps, and a coil surroundingthe armature assembly iormed by said strips and 'said spring.

3. A relay comprising a pair of U-shaped yokes disposed with their legs in spaced confronting relation to form air gaps, an amature assembly comprising a flexible spring of .non-magnetic material xed at one end and two magnetizable strips secured intermediate their ends to the nent magnet connected with said yokes for polarizing said relay.

4. A polar relay comprising two U-shaped yokes secured with their legs in spaced confron ing relation to top and bottom plates of insula ing material, an L-shaped spring of non-magnetic material havingone leg secured to said bottom plate and the other leg extending through the air gaps formed between the legs of said yokes and through an opening formed in said top plate, two magnetizable strips secured intermediate their ends to the opposite sides of said other leg of said spring intermediate its ends and having their ends extending into said air gaps, a coil wound on a single spool surrounding said strips and the associated leg of said spring opposite sides of said spring intermediate its ends I with clearance, a permanent'magnet connected with said yokes for polarizing said relay, and contacts mounted on said top plate and operated by the upper end of said other leg of said spring.

5. A polar relay comprising a pair of magnetizable yokes disposed with their legs in spaced confronting relation and connected with the opposite ends of a permanent magnet, an armature assembly comprising two magnetimble strips secured to the opposite sides of a nonmagnetizable spring, means supporting one end of said spring in such a position that the ends oi' said strips are disposed in the air gaps formed between the legs of said yokes, and a coil surrounding the assembly formed by said strips and said springs, the parts being so proportioned that said assembly will move to a normal or a reverse position according as said coil is supplied with current of no'rmal or reverse polarity and that in moving between its normal and reverse positions said spring will -ilex at a point located approximately at the center of said coil.

NORMAN F. AGNEW. 

